Donated blood used for transfusion and production of blood preparations is roughly classified into donated blood for whole blood donation and donated blood for blood component donation. Various kinds of blood preparations are produced by physically separating components of blood or the like collected by blood donation. For example, whole blood preparations, concentrated erythrocyte preparations, washed erythrocyte preparations, source plasma preparations, and blood plasma fraction preparations, respectively, are produced from blood collected by whole blood donation, and platelet preparations and blood plasma fraction preparations, respectively, are produced from specific blood components collected by blood component donation.
Platelet preparations, which are one kind of blood preparation, are thought to have a high incidence frequency of non-hemolytic transfusion reactions (Japanese Unexamined Patent Application Publication No. S62-290469). Particularly, causes of side effects such as hives, itchiness, and anaphylactic shock seem to be associated with protein (plasma) included in platelet preparations. Therefore, the removal of proteins included in platelet preparations is necessary (Japanese Unexamined Patent Application Publication No. S54-15476). In addition, similarly, erythrocyte preparations have the phenomena of non-hemolytic transfusion side effects. Accordingly, protein removal is necessary also in erythrocyte preparations.
As typical methods of removing proteins included in blood preparations such as erythrocyte preparations and platelet preparations, there are mentioned membrane separation and centrifugation processes. The membrane separation process has been used for separation between erythrocytes and protein (Japanese Unexamined Patent Application Publication Nos. S62-290469 and S54-15476) and the like, and also an improved technique such as a membrane that hardly causes clogging and staining (Japanese Unexamined Patent Application Publication No. S61-238834). On the other hand, it is pointed out that centrifugation easily causes erythrocyte hemolysis and platelet activation (Japanese Unexamined Patent Application Publication No. S61-238834). However, the Japanese Red Cross Society engaged in blood donation throughout Japan produces platelet preparations by centrifugation process so that centrifugation process has been in a dominant position as the method for protein removal.
However, the centrifugation process easily causes erythrocyte hemolysis, platelet activation, and platelet aggregation due to centrifugal force, as well as the process is not sufficient to remove proteins. Moreover, centrifugation process includes a troublesome operation in which the fractionation of a supernatant (a protein portion) requires manual labor. On the other hand, since the platelet concentration of platelet preparations is three times or more than that of whole blood, platelet preparations are blood preparations that extremely easily cause aggregation between platelets. Even in conventional membrane separation processes, contact of platelets with the membrane causes activation and aggregation of platelets. Accordingly, until now there has been a desire for a new means of purifying platelet preparations. In addition, since the centrifugation process causes also erythrocyte hemolysis, a new technique has been desired even in separation of not only a platelet preparation but also a blood preparation through membrane separation process.
Therefore, it could be helpful to provide a hollow fiber membrane for purifying a blood preparation and a hollow fiber membrane module for purifying blood preparations, which allow for deproteinization of the blood preparation so that a highly safe blood preparation can be efficiently obtained.
We provide a polysulfone-based hollow fiber membrane and a hollow fiber membrane module that purifies blood preparations, which are described in (1) to (12) below:
(1) A polysulfone-based hollow fiber membrane that purifies blood preparations, the membrane having a hydrophilic polymer on a surface thereof which contacts the blood preparation, in which the abundance ratio of the hydrophilic polymer is from 40 to 60% by mass, and porosity at the surface is from 8 to 30%.(2) The polysulfone-based hollow fiber membrane according to the above (1), in which the water permeability of the membrane is 20 mL/hr/Pa/m2 or more.(3) The polysulfone-based hollow fiber membrane according to the above (1) or (2), in which the roundness of pores of the surface is 1 or less.(4) The polysulfone-based hollow fiber membrane according to any of the above (1) to (3), in which the membrane is for purifying a platelet preparation.(5) The polysulfone-based hollow fiber membrane according to any of the above (1) to (4), in which the abundance ratio of carbon derived from ester groups on the surface is from 0.1 to 10% by number of atoms.(6) The polysulfone-based hollow fiber membrane according to any of the above (1) to (5), in which the surface is an inner surface of the membrane.(7) The polysulfone-based hollow fiber membrane according to any of the above (1) to (6), in which a void length X of the surface side is larger than a void length Y of a surface side opposite to the surface side.(8) The polysulfone-based hollow fiber membrane according to the above (7), in which a value of the void length X divided by the void length Y is 1.1 or more.(9) The polysulfone-based hollow fiber membrane according to the above (7) or (8), in which the void length X is from 0.1 to 4.0 μm.(10) A hollow fiber membrane module that purifies blood preparations, including the polysulfone-based hollow fiber membrane according to the above (1) to (9).(11) The hollow fiber membrane module according to the above (10), in which a value of an end face length of the module divided by the flow passage cross-sectional area thereof is from 50 to less than 200.(12) The hollow fiber membrane module according to the above (10) or (11), in which a value of an amount of treatment of the blood preparation divided by the surface area of the surface of the hollow fiber membrane, which surface contacts the blood preparation, is from 0.05 to 0.3.
Further, we provide a polysulfone-based hollow fiber membrane that purifies platelet preparations and a hollow fiber membrane module that purifies platelet preparations, which are described in (13) to (23) below:
(13) A polysulfone-based hollow fiber membrane that purifies platelet preparations, the membrane having a hydrophilic polymer on a surface thereof which contacts the platelet preparation, in which the abundance ratio of the hydrophilic polymer is from 40 to 60% by mass, and porosity at the surface is from 8 to 30%.(14) The polysulfone-based hollow fiber membrane according to the above (13), in which the water permeability of the membrane is 20 mL/hr/Pa/m2 or more.(15) The polysulfone-based hollow fiber membrane according to the above (13) or (14), in which the roundness of pores of the surface is 1 or less.(16) The polysulfone-based hollow fiber membrane according to any of the above (13) to (15), in which the abundance ratio of carbon derived from ester groups on the surface is from 0.1 to 10% by number of atoms.(17) The polysulfone-based hollow fiber membrane according to any of the above (13) to (16), in which the surface is an inner surface of the membrane.(18) The polysulfone-based hollow fiber membrane according to any of the above (13) to (17), in which a void length X of the surface side is larger than a void length Y of a surface side opposite to the surface side.(19) The polysulfone-based hollow fiber membrane according to the above (18), in which a value of the void length X divided by the void length Y is 1.1 or more.(20) The polysulfone-based hollow fiber membrane according to the above (18) or (19), in which the void length X is from 0.1 to 4.0 μm.(21) A hollow fiber membrane module that purifies platelet preparations, including the polysulfone-based hollow fiber membrane according to the above (13) to (20).(22) The hollow fiber membrane module according to the above (21), in which a value of an end face length of the module divided by the flow passage cross-sectional area thereof is from 50 to less than 200.(23) The hollow fiber membrane module according to the above (21) or (22), in which a value of an amount of treatment of the platelet preparation divided by the surface area of the surface of the hollow fiber membrane, which surface contacts the platelet preparation, is from 0.05 to 0.3.
The polysulfone-based hollow fiber membrane can remove proteins included in a platelet preparation while suppressing platelet activation. Therefore, the use of the polysulfone-based hollow fiber membrane in a hollow fiber membrane module enables the platelet preparation to be purified efficiently while ensuring high safety. In addition, the polysulfone-based hollow fiber membrane has a function of removing proteins in an erythrocyte preparation while suppressing, particularly, erythrocyte hemolysis. Therefore, the use of the polysulfone-based hollow fiber membrane in a hollow fiber membrane module that purifies an erythrocyte preparation enables the erythrocyte preparation to be purified efficiently while ensuring high safety.